Abstract: Carbon is an important element of life, and its biogeochemical cycle is one of the core contents in the study of coastal wetland. Stable isotope technique is more and more applied in this domain, having improved the research level and promoted the research progress. This paper summarized the advances in the stable isotope research on the carbon biogeochemical cycle in coastal wetland from the aspects of organic matter production, soil organic matter traceability, transferring process of food chain, greenhouse gases emission, and dissolved organic carbon output. The mechanisms and extraneous sources of organic matter production are investigated by the measurement of plant and soil δ¹³C values, the carbon flow in the wetland ecosystem is analyzed through the comparison of the δ¹³C values of various species, and the environmental factors affecting the carbon output of wetland ecosystem are revealed via the measurement of the δ¹³C values of emitted greenhouse gases and dissolved organic carbon. By the end of this paper, the existing problems and the future directions of related studies were discussed and prospected.

Key words: hyperspectral images, partial least squares regression (PLSR), vegetation spectral reflectance, soil heavy metal concentrations, Yushu County.